1. Field of the Invention
The present invention relates to a device and a method for simplifying a description of a travel route.
2. Description of the Related Art
Conventional navigation systems may require that the digital map be replaced owing to an update. In this case, for example, the existing routes that are frequently travelled and are stored in the navigation device can no longer be used because of the possibility that the existing route points, which describe the travel route on the map, can no longer be mapped onto the corresponding route segments on the new map. The reason for this situation may lie, for example, in the fact that the new road map comes from a different map manufacturer using a different geographic map grid than the map manufacturer who delivered the digital map that was used before. In such a case, the stored reference points or route points would then be mapped to positions on the new map that do not lie on the actual road segments. In order to be able to continue to use these stored routes of travel nevertheless, it becomes mandatory to adapt the travel route to the new road map that is to be used. Moreover, the map update can also cause a slight displacement of the roads, for example, when a construction project at a specific position results in an expansion of the road or in the construction of a new traffic circle that is now considered on the new digital map that is to be used. To date the known approaches have not described how such a transfer of the stored routes of travel could be carried out, taking into consideration the new digital map.
The known methods only describe a so-called location referencing system for identifying a place on a digital map of the road network (the so-called coding) and for identifying (by machine) the same place on a second digital map (the decoding). In this case the places, so-called locations, may be individual points, linear route segments, subgraphs or abstract areas. In the past the trend has been to develop location referencing methods with a focus on linear route segments. There exist strategies for transferring networks or subgraphs of the road graph, where the network is decomposed into linear locations. However, to date there is no exact description of how this decomposition functions. In addition, these approaches have not been tested yet.